Ginkgo biloba has been used medicinally for thousands of years. Today, it is one of the top-selling herbs in the United States.

Ginkgo is used for the treatment of numerous conditions, many of which are under scientific investigation. Available evidence supports ginkgo for managing dementia, anxiety, schizophrenia, and cerebral insufficiency (insufficient blood flow to brain).

Evidence for other uses is either lacking or mixed. Further research is needed for all uses of ginkgo.

Although ginkgo is generally well tolerated, it should be used cautiously in people with clotting disorders or taking blood thinners, or prior to some surgical or dental procedures, due to reports of bleeding.

These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.

GRADE *

Cerebral insufficiency is characterized by poor concentration, confusion, decreased physical performance, fatigue, headache, dizziness, depression, and anxiety. Research of ginkgo for cerebral insufficiency has demonstrated efficacy in reducing symptoms. However, additional research is warranted in this area.

B

Overall, the scientific literature suggests that ginkgo benefits people with dementia. Ginkgo may improve cognitive performance and protect against Alzheimer's. However, conclusions regarding ginkgo for dementia are often conflicting. Additional research is needed in this area.

B

From available research, ginkgo offers benefit to people with generalized anxiety disorder (GAD). Further research is needed to confirm dosing and who may benefit most from ginkgo.

B

Research suggests that in combination with antipsychotics, ginkgo may offer benefits for people with schizophrenia. Additional research is needed on this topic.

B

Research on ginkgo for the treatment of altitude (mountain) sickness reports conflicting results. Additional research is needed before a firm conclusion can be made.

C

Ginkgo extract or a ginkgo combination product may reduce asthma symptoms. Further research is required before a conclusion can be drawn.

C

Limited research suggests that ginkgo is less effective than methylphenidate for symptoms of ADHD. Studies using combination therapies with ginkgo suggest benefits for ADHD symptoms. Further research on ginkgo alone is needed on this topic.

C

Ginkgo may reduce behaviors and symptoms of autism. Further well-designed research is needed before a conclusion can be made.

C

Conclusions on the effects of ginkgo on blood pressure control are lacking. Further research is needed is this area before a conclusion can be made.

C

Ginkgo lacked an effect on the cancer development in people taking ginkgo. Ginkgo also lacked protective effects on bladder cancer risk. Further research is needed on this topic.

C

There is inconclusive evidence regarding the efficacy of ginkgo to reduce the vascular adverse effects associated with some chemotherapy, such as 5-fluorouracil (5-FU). Further studies are required on this topic.

C

There is limited available evidence of the effect of ginkgo in chronic cochleovestibular disorders. Further trials are required before conclusions may be drawn.

C

Ginkgo may widen and relax blood vessels. A combination product containing ginkgo may aid in treating people with lower limb chronic venous insufficiency. Further research is needed in this area.

C

Ginkgo may improve claudication symptoms. However, improvements in the absolute claudication distance were lacking in some studies. Additional evidence from high-quality trials is still needed before conclusions may be drawn.

C

Ginkgo has also been found to increase chemicals from the brain. It is not clear whether ginkgo is helpful in treating cocaine dependence. Further research is needed in this area.

C

According to limited research, ginkgo may improve cognitive function in people with multiple sclerosis (MS) and vascular cognitive impairment no dementia (VCIND). However, other research found benefits were lacking. More well-designed studies are needed before a firm conclusion may be made.

C

It has been postulated that Ginkgo may be effective for treating erectile dysfunction. Ginkgo may help dilate blood vessels. However, additional research is needed in this area.

C

There is insufficient available evidence regarding the use of ginkgo for depression or seasonal affective disorder.

C

The effect of ginkgo has been studied on various endpoints in people with diabetic nephropathy. Benefits were observed in parameters of kidney function. Further research is required before conclusions may be drawn.

C

Ginkgo in combination with B vitamins lacked an effect on symptoms of diabetic neuropathy vs. B vitamins alone. Further research is needed.

C

Ginkgo is traditionally used for improved memory or cognition. Preliminary results suggest that Ginkgo may be of benefit for dyslexia. More studies are required before conclusions may be drawn.

CoQ10 and ginkgo improved quality of life and self-rating scores in people with fibromyalgia. Further research is needed on the effects of ginkgo alone for this use.

C

Research suggests that ginkgo lacks an effect on glaucoma. Ginkgo may benefit other aspects of eye health, such as increasing blood flow and protecting against visual field damage. Further research is needed in this area.

C

Ginkgo's potential antioxidant properties may reduce toxicity associated with iodine-131 therapy. Further studies are required before firm conclusions may be made.

C

In individuals with hearing loss, a higher dose of ginkgo was more effective than a lower ginkgo dose. Ginkgo may decrease the ear inflammation and improve hearing. Well-designed research is still needed in this area.

C

Ginkgo may have positive benefits on blood flow and relax blood vessels. However, ginkgo may lack benefit on other cardiovascular events. Further studies are required in this area.

C

In early research, ginkgo was effective in the treatment of people with hemorrhoids. Components of ginkgo may also reduce pain and bleeding associated with hemorrhoids. Additional research is needed to confirm these results.

C

Effects of Ginkgo on insulin and glucose responses were lacking in people with type 2 diabetes, prediabetes, or normal glucose tolerance. Further research is needed.

C

Preliminary research suggests that ginkgo may have antioxidant effects and improve eye blood flow. It remains unclear if macular degeneration is significantly affected by ginkgo. More research is needed in this area before a conclusion can be drawn.

C

Evidence is mixed with respect to the use of Ginkgo for memory enhancement in healthy individuals. Additional research is needed in this area.

C

The effect of Ginkgo on mental alertness after eating is unclear. Ginkgo may have positive benefits on some but not all endpoints. Further study is needed on this topic.

C

Various trials have examined the effects of ginkgo as part of migraine treatment. Overall, these studies suggest an evidence of benefit in children and women. Further well-designed research is needed investigating the effects of Ginkgo itself.

C

In early research, ginkgo appeared to have modest beneficial effects on mood and cognition in postmenopausal women. However, use of the multi-ingredient product Gincosan® lacked significant effects. Further research using ginkgo alone is needed to confirm these results.

C

Ginkgo's anti-inflammatory and platelet-activating factor (PAF)-inhibiting properties may help treat multiple sclerosis (MS). However, well-designed trials showing benefits are lacking. Further research is needed in this area.

C

Early research suggests that the addition of Ginkgo may improve allergy symptoms in the eye. Well-designed research is still needed for this topic.

C

There is insufficient evidence to draw conclusions ginkgo use for premenstrual syndrome (PMS). Well-designed studies are needed in this area.

C

In early research, ginkgo was found to be effective in treating pulmonary interstitial fibrosis. Further research is needed to confirm these results.

C

A few studies have suggested that Ginkgo may aid in quality of life. More research is needed before a conclusion may be made.

C

Early research suggests that ginkgo extract benefit to people with retinopathy. However, sufficient evidence is still lacking to draw a conclusion. Further studies are required in this area.

C

A gel base containing ginkgo was effective for skin moisturizing, skin smoothness and wrinkle reduction. More research is needed in this area.

C

Ginkgo was found to lack additional benefit over glucocorticoids alone for loss is smell. Further research is needed before a conclusion can be made.

C

Limited evidence suggests ginkgo may reduce tumor volume. Further human studies are required before conclusions may be drawn.

C

Laboratory studies suggest that ginkgo may be helpful immediately following strokes, because of possible antioxidant or blood vessel effects. However, initial study of ginkgo in people having strokes found a lack of benefit. Further research is needed in this area.

C

There is conflicting research regarding the use of ginkgo for tinnitus. Additional well-designed research is needed in order to resolve this controversy.

C

There is inconclusive evidence regarding ginkgo for the treatment of vertigo. Additional research is needed to draw a conclusion.

C

Limited research has investigated the efficacy of ginkgo for vitiligo. Further well-designed studies are required on this topic.

C

Age-associated memory impairment (AAMI) is a nonspecific syndrome, which may be caused by early Alzheimer's disease or multi-infarct dementia. Overall evidence does not support benefits of Ginkgo for memory loss. Further studies are needed before a firm conclusion can be made.

D

Limited research suggests that ginkgo may be effective in reducing the number of attacks in people with Raynaud's disease (RD). However, other studies reported that significant changes were lacking. In order to make firm conclusions, further research is required.

D

* Key to grades

A: Strong scientific evidence for this useB: Good scientific evidence for this useC: Unclear scientific evidence for this useD: Fair scientific evidence for this use (it may not work)F: Strong scientific evidence against this use (it likley does not work)

Tradition / Theory
The below uses are based on tradition, scientific theories, or limited research. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider. There may be other proposed uses that are not listed below.

For age-associated memory impairment (AAMI), 240-600 milligrams of ginkgo extract (EGb 761® or ginkgobene®) has been taken by mouth for up to 42 weeks. Ginkgo in a dosage of 0.9-1.9 milliliters has been taken by mouth three times daily. Additionally, 120 milligrams of ginkgo extract has been taken by mouth twice daily for 6.1 years.

For altitude (mountain) sickness, 160 milligrams of ginkgo (EGb 761®) once daily or 120 milligrams of ginkgo twice daily has been taken by mouth for 4-5 days.

For autism, 100 milligrams of ginkgo EGb 761® has been taken by mouth daily for four weeks.

For blood pressure control, 120 milligrams of ginkgo extract has been taken by mouth for 6.1 years.

For cancer prevention, 120 milligrams of ginkgo extract (EGb 761®) has been taken by mouth twice daily for 6.1 years.

For cerebral insufficiency (insufficient blood flow to the brain), up to 160 milligrams of ginkgo has been taken by mouth daily for 12 weeks in up to three divided doses.

For cochleovestibular (ear) disorders, 160 milligrams of ginkgo (EGb 761®) supplements (Tanakan® or Tebokan®) has been taken by mouth as two tablets twice daily over six weeks.

For claudication (leg pain from clogged arteries), 80-320 milligrams of ginkgo extract (EGb 761®) or 6 milliliters of ginkgo liquid has been taken by mouth daily in single or divided doses for up to six months. The ginkgo product Tanakan® has been injected in the veins at a dose of 100 milligrams in 500 cubic centimeters of normal saline, twice daily for eight days. Additionally, 35 milligrams of ginkgo extract has been injected into the femoral vein.

For cocaine dependence, 120 milligrams of ginkgo has been taken by mouth daily for 10 weeks.

For cognitive performance, up to 600 milligrams of ginkgo has been taken by mouth as a tablet, flavone glycoside, ginkgolide, or leaf extract in single or divided doses for up to eight months (Blackmore's ginkgo Forte®, EGb 761®, Tebonin®, Tanakan®, Rökan®, Kaveri®).

For decreased libido and erectile dysfunction (impotence), up to 240 milligrams of ginkgo or ginkgo extract has been taken by mouth daily for up to 18 months.

For dementia, up to 600 milligrams daily of ginkgo in single or divided doses has been taken by mouth for up to six years (EGb 761®, Tebonin®, Tanakan®, Rökan®, Kaveri®). Additionally, 200 milligrams of EGb 761® has been injected in the blood for four days weekly. Geriaforce® at a daily dose of 2.85-5.7 milliliters has been injected in the blood for 24 weeks.

For depression and seasonal affective disorder (SAD), 240 milligrams of ginkgo has been taken by mouth for up to 10 weeks.

For diabetic nephropathy (kidney damage), 20 milliliters of ginkgo in 250 milliliters of normal saline has injected in the blood daily for four weeks.

For eye allergy, two eyedrops containing a combination of ginkgo and hyaluronic acid were used in each eye three times daily for one month.

For generalized anxiety disorder, 240-480 milligrams of ginkgo has been taken by mouth daily in up to three divided doses for 4-8 weeks.

For glaucoma (increased eye pressure), up to 300 milligrams of ginkgo, ginkgo extract or flavonoid glycosides has been taken by mouth daily in single or divided doses for up to four years.

For glucose tolerance, 120 milligrams of EGb 761® has been taken by mouth once daily for three months.

For Graves' disease (thyroid disorder), 120 milligrams of EGb 761® has been taken by mouth daily from three days before to 30 days after radioiodine therapy.

For hearing loss, 120 milligrams of ginkgo has been taken by mouth twice daily. Additionally, 40 milligrams of ginkgo has been taken by mouth three times daily over two different courses of 90 days.

For heart disease, 120 milligrams of ginkgo extract (EGb 761®, Schwabe Pharmaceuticals, Karlsruhe, Germany) has been taken by mouth twice daily for 6.1 years. Additionally, 87.5 milligrams of ginkgo extract has been injected in the blood daily for two weeks.

For macular degeneration (eye disease), up to 480 milligrams of ginkgo or ginkgo extract has been taken in single or divided doses by mouth for up to six months (ginkgo extract LI 1370, EGb 761®).

For memory enhancement, 120-360 milligrams of ginkgo daily in single or divided doses has been taken by mouth for up to six weeks (Bioginkgo® , Ginkoba® , Blackmore's ginkgoforte extract, Li1370, EGb 761®, Ginkoba Gb extract).

For mental alertness (post-meal), 130-234 milligrams of ginkgo daily has been taken by mouth for 13 weeks.

For mood and cognition in postmenopausal women, 120 milligrams of ginkgo has been taken by mouth daily for seven days to six weeks.

For multiple sclerosis (MS), 240 or 360 milligrams of ginkgolide B has been taken by mouth daily.

For premenstrual syndrome (PMS), up to 320 milligrams of ginkgo or ginkgo extract has been taken by mouth in single or divided doses (Ginko T.D.T EGb 761®).

For pulmonary interstitial fibrosis (lung scarring), 1 gram of ginkgo extract has been taken by mouth three times daily for three months.

For quality of life, 120 milligrams of EGb 761® extract has been taken by mouth daily for 4-10 months.

For Raynaud's (poor circulation), 120-360 milligrams of ginkgo extract (EGb 761®) has been taken by mouth in single or divided doses daily for up to 10 weeks.

For retinopathy (eye damage from type 2 diabetes), 80 milligrams (2 milliliters) of EGb 761® has been taken by mouth twice daily.

For schizophrenia, up to 360 milligrams of ginkgo or ginkgo extract (EGb 761®) has been taken by mouth in divided doses daily for up to 16 weeks, alone or in combination with antipsychotics.

For smell disorders, 80 milligrams of ginkgo has been taken by mouth three times daily for four weeks in addition to prednisolone and mometasone furoate.

For stroke, 40 milligrams of ginkgo has been taken by mouth four times daily for four weeks.

For stomach cancer, 0.5 grams of ginkgo has been taken by mouth three times daily.

For tinnitus (ringing of the ears), up to 240 milligrams of ginkgo or ginkgo extract has been taken by mouth in single or divided doses for up to 26 weeks (EGb 761®, Tanakan®, LI1370). Additionally, 200 milligrams of EGb 761® has been injected in the blood for 10 days, followed by 80 milligrams taken by mouth twice daily for 12 weeks.

For vertigo (dizziness), 160 milligrams of ginkgo (EGb 761®) has been taken by mouth daily for three months.

For vitiligo (lack of pigment in the skin), 120 milligrams of ginkgo extract or standardized ginkgo in two or three divided doses has been taken for up to six months.

Note: The intravenous ginkgo product Tebonin®, which was available in Germany, may have been removed from the German market due to significant adverse effects.

Note: Beneficial effects may take 4-6 weeks to appear. Ginkgo seeds are potentially toxic and should be avoided.

Children (under 18 years old)

For attention-deficit hyperactivity disorder (ADHD), 40-120 milligrams has been taken by mouth daily in single or divided doses for six weeks.

For dyslexia, 80 milligrams of EGb 761® has been taken by mouth daily for an average of 34.4 days.

Safety
The U.S. Food and Drug Administration does not strictly regulate herbs and supplements. There is no guarantee of strength, purity or safety of products, and effects may vary. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy. Consult a healthcare provider immediately if you experience side effects.

Allergies

Avoid in people with a known allergy or sensitivity to Ginkgo biloba, its parts, or members of the Ginkgoaceae family. There is possible cross-sensitivity in people allergic to urushiols (mango rind, sumac, poison ivy, poison oak, cashews).

Side Effects and Warnings

Ginkgo appears to be safe when taken by healthy adults by mouth in suggested doses for up to six months. The most concerning potential complication is bleeding, which has been life threatening in a small number of reports.

Ginkgo may cause higher or lower blood pressure. Caution is advised in people taking drugs or herbs and supplements that alter blood pressure.

Drowsiness or sedation may occur. Use caution if driving or operating heavy machinery.

Ginkgo may lower blood sugar levels. Caution is advised in people with diabetes or hypoglycemia, and in those taking drugs, herbs, or supplements that affect blood sugar. Blood glucose levels may need to be monitored by a qualified healthcare professional, including a pharmacist, and medication adjustments may be necessary.

Use cautiously in people with a history of or at risk of stomach or intestine disorders, musculoskeletal disorders, nervous system disorders, psychiatric disorders, seizures, or skin disorders. Use cautiously in people at risk of Stevens-Johnson syndrome. Use cautiously in children, women trying to conceive, and pregnant or breastfeeding women.

Use cautiously in people taking agents for heart disease or seizures, anticholinergic agents, antidepressants, CYP450-metabolized agents, or St. John's wort. Use cautiously in people undergoing electroconvulsive therapy (ECT).

Ginkgo may increase the risk of bleeding. Avoid in people with bleeding disorders or taking drugs that may increase the risk of bleeding. Dosing adjustments may be necessary.

Avoid ingesting ginkgo seeds or pulp, due to potential adverse effects. Avoid 2-3 weeks prior to some surgical and dental procedures. Avoid in people with heart disease. Avoid ginkgo injected in the blood. Avoid consuming or handling with known allergy or hypersensitivity to Ginkgo biloba, its constituents, members of the Ginkgoaceae family, or urushiols (mango rind, sumac, poison ivy, poison oak, cashews), due to cross-reactivity potential.

Ginkgo may lower blood sugar levels. Caution is advised when using medications that may also lower blood sugar. People taking drugs for diabetes by mouth or insulin should be monitored closely by a qualified healthcare professional, including a pharmacist. Medication adjustments may be necessary.

Ginkgo may increase the risk of bleeding when taken with drugs that increase the risk of bleeding. Some examples include aspirin, anticoagulants ("blood thinners") such as warfarin (Coumadin®) or heparin, anti-platelet drugs such as clopidogrel (Plavix®), and non-steroidal anti-inflammatory drugs such as ibuprofen (Motrin®, Advil®) or naproxen (Naprosyn®, Aleve®).

Ginkgo may interfere with the way the body processes certain drugs using the liver's "cytochrome P450" enzyme system. As a result, the levels of these drugs may be altered in the blood, and may cause increased effects or potentially serious adverse reactions. People using any medications should check the package insert, and speak with a qualified healthcare professional, including a pharmacist, about possible interactions.

Ginkgo may lower blood sugar levels. Caution is advised when using herbs or supplements that may also lower blood sugar. Blood glucose levels may require monitoring, and doses may need adjustment.

Ginkgo may increase the risk of bleeding when taken with herbs and supplements that are believed to increase the risk of bleeding. Multiple cases of bleeding have been reported with the use of Ginkgo biloba, and fewer cases with garlic and saw palmetto. Numerous other agents may theoretically increase the risk of bleeding, although this has not been proven in most cases.

Ginkgo may interfere with the way the body processes certain herbs or supplements using the liver's "cytochrome P450" enzyme system. As a result, the levels of other herbs or supplements may become altered in the blood. It may also alter the effects that other herbs or supplements possibly have on the P450 system.

The information in this monograph is intended for informational purposes only, and is meant to help users better understand health concerns. Information is based on review of scientific research data, historical practice patterns, and clinical experience. This information should not be interpreted as specific medical advice. Users should consult with a qualified healthcare provider for specific questions regarding therapies, diagnosis and/or health conditions, prior to making therapeutic decisions.